Impact of Early Blood Pressure Reduction on Prognosis in ICU Patients with Severe Acute Hypertension: A Retrospective Study of the Medical Information Mart for Intensive Care IV (MIMIC-IV) Database

Severe acute elevations in blood pressure (BP) are common among intensive care unit (ICU) patients and are associated with adverse clinical outcomes. This study investigated the association between early BP dynamics following severe acute hypertension and 30-day mortality. In this retrospective cohort study using the Medical Information Mart for Intensive Care IV (MIMIC-IV) database, we included 4 895 ICU patients with severe acute hypertension, defined as at least one systolic blood pressure (SBP) measurement ≥ 180 mmHg. Restricted cubic spline (RCS) models were used to characterize the associations between 30-day mortality and four BP parameters measured 1 hour after the index episode: achieved systolic and diastolic BP (SBP-1h and DBP-1h) and their corresponding percent reductions (SBP-PR and DBP-PR). Survival analyses were conducted across predefined BP strata. The greatest reduction in BP occurred within the first hour after the index hypertensive episode. RCS analyses demonstrated U-shaped associations between 30-day mortality and both SBP-1h and SBP-PR, with nadirs at 156.76 mmHg for SBP-1h and 14.87% for SBP-PR. In multivariable Cox regression models, an SBP-1h of 140–180 mmHg or an SBP-PR of 5%-25% was associated with a significant survival benefit. Conversely, a DBP-1h < 70 mmHg or a DBP-PR > 27% was associated with an increased risk of mortality. Among ICU patients with severe acute hypertension, maintaining BP within an optimal range during the early treatment period is associated with improved prognosis. Excessive reductions in either SBP or DBP are associated with increased 30-day mortality, highlighting the importance of avoiding overaggressive BP lowering in this population.